1. Field of the Invention
The present invention relates to a seat belt system, more particularly to a automobile seat belt system which can automatically tighten and untighten the seat belts in accordance with the condition of the driver.
2. Description of the Prior Art
Seat belt systems are now standard equipment for automobiles in many countries. Conventional seat belt systems, of course, are designed only to protect the driver or passenger in the event of accidents and are powerless to prevent accidents due to a driver falling asleep at the wheel, drunken driving, etc.
On another matter, conventional seat belt systems include a seat belt and a seat belt winding device having a spring for winding up and removing belt slack. Due to this arrangement, the driver or passenger is continuously subjected to a fixed tension from the seat belt. This creates an unpleasant sensation and restricts freedom of motion, thereby often prompting detachment of the seat belt or even removal of the entire system.